The remote keys contain 3 different technologies (EWS/FZV/DWA) which work in conjunction with each other. The problems you describe sounds like you're having issues with FZV & DWA.

Here's a link to a BMW Technical document (PDF) that goes into detail about FZV (central locking system) as well as DWA (anti-theft alarm siren system) in way more details than I can write...maybe it can help explain some of the issues you are having: http://www.bmwmotorsports.org/BMW_do...lectronics.pdf